On the Ski Slopes With Avalanche Patrollers

In 2009, 54 people in North America lost their lives to avalanches. Three of those deaths occurred at ski areas. That's not supposed to happen—ever. But there's one thing you learn bombing slopes on dawn patrol at places like Big Sky, Montana: In the mountains, you're never completely safe.

The bomb is the size of a soup can, bright orange, stuffed with two pounds of pentolite--a chalky mixture of TNT and an even more powerful explosive compound known as PETN. Ross Titilah, a 31-year-old ski patroller at Big Sky Resort in southern Montana, ties the bomb to one end of a short nylon rope and triggers the igniter. Ninety seconds until detonation. The other end of the rope is attached to what's known as a bomb tram--a sort of ski lift for explosives that stretches from one fin of rock to another high above the entrance to a steep gully in Big Sky's experts-only area.

The tram is cranked by hand, using a pulley system assembled from parts of an old chairlift, and Ross hurriedly rotates the wheel until the bomb is dangling over the center of the gully, several feet above the snow--giving the shock waves more room to do their work. Ross crouches down, amid swirling snow, and shouts into his radio: "Fire in the hole!"

It's a little after sunrise on March 5, 2009, after a night of intense snowfall, nearing the end of what will prove to be one of the most frightening avalanche seasons in memory, with a total of 54 fatalities in the United States and Canada. That's an average of more than three deaths a week during the height of the season, and the second highest tally since record-keeping began in 1950. But it's not the number of fatalities that made the season so nerve-wracking for patrollers; it's where they took place. Usually, avalanche deaths happen in the backcountry, away from an established ski area. Even a single in-bounds fatal avalanche is considered unusual.

Last winter, there were three. A 27-year-old woman was buried in a slide at Snowbird, Utah; a 21-year-old man was killed at Squaw Valley, Calif.; and a 31-year-old man was swept away in Jackson Hole, Wyo. All the incidents took place on steep, difficult terrain, much like the gullies where Ross and his patrol partner, Steve Emerson, are working now. The Jackson death was especially troubling, since the skier was wearing both a helmet and an avalanche transceiver--a homing device, worn around the torso, that greatly aids in a speedy rescue--and was found by other skiers within 8 minutes. It was still too late. One avalanche forecaster in British Columbia said that North America hadn't seen such unstable conditions in at least 100 years.

Less than 48 hours before my visit, another tragedy took place. A veteran patroller at Squaw Valley, attempting to make a slope safe for the public, was killed in a slide. Patrollers are a tight bunch--fewer than 5000 pros work in the United States, and they frequently visit other areas to swap knowledge and techniques. A fatality impacts the whole community, which is why the Big Sky patrol locker room, normally chatty and caffeinated even in the pre-dawn dark, felt somber and a touch nervous when I arrived.

Big Sky is one of the more awe-inspiring resorts in North America, centered around a solitary pyramidal mountain--Lone Peak--which can be skied right from the summit. I arrived following one of the winter's biggest storms, which dropped more than a foot of snow amid fierce winds. The easiest thing to do, when faced with an unstable snowpack, is simply keep most of the mountain closed. Sometimes this happens. But a patroller's job is a tricky juggle between mitigating natural dangers and satiating skiers' desires. To an avid skier or snowboarder, there's nothing more joyful than flying through steep, untracked snow--precisely the scenario that's most uncertain in terms of stability. The compromise is that, after a storm, the patrol activates the most slide-prone areas by detonating powerful explosives.

High on the flanks of Lone Peak, in the moments before the bomb hanging from the tram is set to explode, Ross and Steve instinctively scan the surrounding slopes, reading the terrain with practiced eyes. "Flagged there," says Ross, indicating a line of evergreens whose branches have been sheared off on one side where previous avalanches have swept close by. "Point release," Steve says, motioning with his chin to a spot where a cliff band, warmed by the rising sun, is naturally shedding the new powder, sloughing little waterfalls of snow.

There's a flash, and a bang--and, for a second, nothing. Then, from down in the gully comes a loud and disconcerting whooomp, as if an overloaded bookshelf has snapped its supports and dropped onto the shelf below it, which is close to what has happened. Abruptly, what had looked like an inviting ski run is transformed into a tumbling, churning mass of snow, blasting down the hill--avalanches often exceed 90 miles per hour--leaving in its wake a billowing cloud of snow mist, gorgeous and daunting at once.

This is a relatively small slide. The vertical crown face at the top of the avalanche path--which indicates the depth of the snow slab that broke away--is only a foot tall. Some slides at Big Sky have 13-foot crowns. Still, it's easy to see how, if a skier is caught in an avalanche, escape is virtually impossible. Once the slide is over, though, the slope is considerably safer; it's like a rubber band that has snapped, its tension dissipated.

One of the most terrifying situations imaginable is to be buried in an avalanche. I know this from firsthand, albeit highly controlled, experience. Several seasons ago, I volunteered to help with the training of Big Sky's avalanche-rescue dogs, which must learn how to sniff out victims trapped beneath the snow. I crawled into a 6-foot-deep hole and created a breathing space by cupping my hands in front of my face as patrollers shoveled snow over me. I am not typically a claustrophobic person, and I knew this was a carefully monitored exercise. That said, the 10 minutes that elapsed before the dog found me rank as some of the most frightening of my life. The snow, even just a few feet under, is pitch-dark. It's extraordinarily heavy. I couldn't move. My breathing, clipped and panicky, was amplified in my ears. I've never felt happier to have a dog lick me across my face.

No matter how experienced a ski patroller is, the danger of a particular slope can never be evaluated perfectly. All three in-bounds deaths last winter came on runs that patrollers had deemed safe. All had been bombed, and one had slid.

Avalanche danger is present when two layers of snow, on a moderately steep slope, do not adequately adhere to each other. Every snowstorm has a unique signature. Different flakes--needles, prisms, dendrites, columns, plates--fall at different temperatures, in varying levels of humidity, and are then baked by fluctuating degrees of solar radiation. When a patroller digs a pit to examine the snowpack, the layer left by each snowstorm can be seen distinctly, like the striations in the walls of the Grand Canyon.

If two adjoining layers are poorly bonded, there's a fault line in the snow--one that, it's hoped, is dislodged by the force of a bomb. But a ski slope can be akin to a minefield. Throw a charge in one spot, and nothing may happen. Put the weight of a skier on another spot just minutes later, and the upper layer can collapse onto the lower and begin to slide--slabs of snow moving downhill like a load of mattresses sliding off a dump truck, escalating in speed and power.

Big Sky has lost two patrollers, one in 1982, in an avalanche, and another on Christmas morning, 1996, when a patroller thought a bomb's fuse had gone out and was attempting a relight when it exploded. Now, every bomb in Big Sky is threaded with two fuses, and is set off by yanking pull-tab igniters.

"Just one mistake on this job can kill you," says Bob Dixon, director of the Big Sky patrol, which includes 8 women, 50 men and a half-dozen dogs, including two Australian shepherds and a chocolate Lab named Mowgli. "But no matter how careful you are, you always deal with the unpredictable. Avalanche control is 30 percent science, 50 percent art and 20 percent luck."

Researchers are hoping to shift these percentages in science's favor. The world's major avalanche-study centers are widely scattered--in Davos, Switzerland; in Nagaoka, Japan; and just an hour up the road from Big Sky, at Montana State University in Bozeman. Last October, under the direction of engineering mechanics professor Ed Adams and another faculty member, Montana State opened its Cold Climate Simulation Chamber, a room in which the ceiling is chilled to minus 58 F and an artificial sun shines on a one-square-meter slope. The goal is to home in on the conditions that create the strongest and weakest bonds between layers of snow. "There's a mystique that it's difficult to accurately predict avalanches," Adams tells me when I visit the lab. "But snow is just a material--though it is a very complicated one."

Along with a company called ThermoAnalytics and experts at the Swiss Federal Institute for Snow and Avalanche Research in Davos, Adams has developed software packages that promise to boost the accuracy of avalanche forecasts. But for now, away from the laboratory, the work is still a mix of science and instinct that entails long hours--the first patrollers arrive at Big Sky before 4:30 am--and lots of explosives.

By the time the mist settles from the first bomb Ross and Steve set, they've already skied to the next slide path. Here, Steve hangs a bomb from the limb of a dead tree. It's a tricky work environment: Howling wind hampers voice communication, dense fog has eliminated most visibility, the slope they're standing on could slide at any moment, and of course they are handling deadly explosives. "Our lives are literally in each other's hands," Ross says, brushing off the icicles that have taken root in his reddish-blond beard.

Ross grew up in the mountains of New Hampshire but fell in love with the Rockies. "I became a patroller," he says, "after I failed college philosophy because I'd spent too much time on the ski hill." He and Steve work with a practiced synchronicity and few words--hand gestures, clipped phrases--as they set off bombs in slide areas. Avalanches tumble; the smell of sulfur hangs in the air; a spray of black powdery residue stains the snow.

Across the resort, 13 more teams are working to clear their own patches of turf. Explosions blast and echo across the cliff faces. The patrollers use three types of explosives. Ross and Steve are using cast primers. Gel shots, which are fat sticks of dynamite, are less powerful but have other advantages--for one, they do not leave black-powder remains and thus are better for south-facing slopes, where powder heated by direct sunlight could create large melt areas. ANFO, ammonium nitrate fuel oil, essentially a large bag of fertilizer, can be detonated with either of the other two.

Big Sky also uses two Buck Rogers-looking cannons, called Avalaunchers, which are powered by nitrogen gas that propels cast primers--each fitted with a plastic nose cone, fins and a trigger that detonates on impact only--high onto dangerous-to-reach cliff bands. As the early morning progresses, teams zip by on snowmobiles; one patroller, working out of a cramped communications center at the mountain's base, monitors everyone's position. And the resort is open to the public by 9:05 am.

Once the avalanche-control work is finished, many of the patrollers hang out in one of the lift-top huts, swapping stories, telling jokes and waiting for a call if medical help is needed. At one hut, Jay Frisque, better known as Magnum ("Because his patroller number is 44, and because he's a badass," Ross says), has cooked up antelope sausage burritos over a portable stove for a crowd of hungry patrollers. It's an addictive profession, Magnum says, grinning slyly--so long as you crave horrible weather, sweaty co-workers and a guarantee that you'll never be rich. "There isn't a person in this room," he adds, "that I wouldn't risk my life for. Or bail out of jail."

The day ends where it begins--in the patrol locker room. In a posh resort like Big Sky, the locker room is the equivalent of a teenager's back-of-the-garage hangout. Stickers are pasted everywhere. A couple of slices of old pizza are strewn on the floor. One ski, cracked in half and mounted on the wall, is signed by a patroller who got buried in an avalanche and was dug out by co-workers. There's also a ski from each of the two Big Sky patrollers who have died on the job.

I conduct a precise inventory of the locker-room's refrigerator: 216 cans of Pabst Blue Ribbon beer and nothing else--not so much as a packet of ketchup. (A patroller needs to bring a case of beer every time he or she commits what's known as an R.B.O.--a round-buying offense--which includes such infractions as getting your backpack stuck in the slats of a chairlift or taking a big fall in front of the public.)

Beers are distributed as the afternoon wanes, but no one pops the top, or starts to change out of uniform, until the last of the on-duty patrollers enter the locker room. That's a strict patroller tradition, I'm told. They won't even take their boots off until everyone is safely home.